1. Field of the Invention
The present invention relates generally to a signal processing apparatus and a signal receiving apparatus, which are suitable for realizing distribution services with the other networks of a digital broadcast program which is being broadcast by a selected network. More specifically, the present invention relates to a signal processing apparatus that can limit the viewing of a program easily and freely by detecting the NIT (Network Information Table) of a digital broadcast data in a first network, deleting information of the program to be limited for viewing among the various pieces of information included in the NIT and then attaining the digital broadcast data in a second network by replacing the NIT of the digital broadcast data in the first network with the NIT from which the information of the program explained above is deleted. Moreover, the present invention also relates to a receiving apparatus for preventing confusion of viewers by displaying no program guide information in relation to the program information not existing in the NIT among those detected from the digital broadcast data.
2. Description of the Related Art
Here, it is thought that a digital broadcast program being broadcast by a selected desired network is distributed by the other networks, for instance, a satellite digital multi-channel broadcast is distributed with a modulating conversion transmitting apparatus or the like by making use of the network provided within the facility of cable television company.
In this case, since a digital broadcast data has NIT including physical information in relation to transmission route, a digital broadcast program being broadcast by the first network cannot be distributed with the second network only by converting a modulating method with the modulating conversion transmitting apparatus or the like. Thus, transmission frequency information or the like included in the NIT of the digital broadcast data is applied to the second network.
Incidentally, NIT includes a program information, and a set top box (customer premises equipment) connected to the transmission route of the cable television, for example, detects NIT and receives the predetermined program on the basis of the program information included in the NIT.
For example, on the occasion of distributing a satellite digital multi-channel broadcast with the modulating conversion transmitting apparatus or the like using the network in the facilities of the cable television company, there may be cases where it is better to give limitation for viewing even when a program exists on the transmission route of the cable television.
Moreover, in these years, it has been proposed, in the satellite broadcast receiver, to detect a program guide information from the digital broadcast data and display such program guide information on a display unit for the convenience of viewers such as selection of program, etc. However, the program information included in NIT does not correspond to the program guide information on one to one basis. In this case, when the program guide information, in which the program does not correspond to the program information included in NIT and thus cannot be received, is displayed, such program is not received even when such program is selected based on the program guide information. This probably causes confusion for viewers.
It is therefore an object of the present invention to provide a signal processing apparatus for limiting viewing of a program easily and freely.
Moreover, it is also an object of the present invention to provide a receiving apparatus for preventing confusion of the viewers.
The signal processing apparatus according to the present invention is a signal processing apparatus for converting a first digital broadcast signal of the predetermined transmitting frequency on the first network to a second digital broadcast signal of the predetermined transmitting frequency on the second network. The signal processing apparatus preferably comprises a first frequency converting means for obtaining a first digital modulation signal by frequency-converting the first digital broadcast signal, a demodulating means for obtaining a digital broadcast data by demodulating the first digital modulation signal, a table detecting means for detecting NIT including the transmitting frequency information and program information from the digital broadcast data transmitted from such demodulating means, a first table changing means for changing at least transmission frequency information of NIT detected by the table detecting means to the information to be applied to the second network, a second table changing means for deleting information relating to the program to be limited for viewing among the program information of NIT detected by the table detecting means, a table replacing means for replacing NIT of the digital broadcast data transmitted from the demodulating means to NIT changed by the first and second table changing means, a modulating means for obtaining the second digital modulated signal by modulating the digital broadcast data in which NIT is replaced in the table replacing means, and a second frequency converting means for obtaining the second digital broadcast signal by frequency-converting the second digital modulated signal.
In the present invention, the first digital broadcast signal on the first network has the predetermined transmitting frequency, but this first digital broadcast signal is frequency-converted to the digital modulated signal and moreover it is then demodulated. Thereby, the digital broadcast data in the first network can be obtained. The digital broadcast data in the first network has NIT including the transmitting frequency information and program information. NIT is detected from the digital broadcast data in this first network and at least the transmitting frequency information is changed to be applied to the second network. Further, information of the program to be limited for viewing among the program information of NIT is deleted.
Here, NIT of the digital broadcast data in the first network is changed so that the transmitting frequency information or the like is changed to be applied to the second network. NIT of the digital broadcast data in the first network is then changed to the NIT from which information of the program to be limited for viewing is deleted. This provides the digital broadcast data in the second network. The digital broadcast data in this second network is modulated to a digital modulated signal and is then frequency-converted to obtain the second digital broadcast signal transmitted by the second network.
The receiving apparatus for receiving the predetermined program based on the program information of NIT does not receive the program other than the one existed in the program information of NIT. Therefore, as explained above, when a program exists on the transmission route, viewing of this program can be limited by deleting the information of the program to be limited for viewing among the program information of NIT.
Moreover, the receiving apparatus according to the present invention is based on a receiving apparatus for detecting NIT including program information from the digital broadcast data and receiving the predetermined program on the basis of the program information of NIT. This receiving apparatus preferably comprises a table detecting means for detecting NIT from the digital broadcast data, an information detecting means for detecting the program guide information from the digital broadcast data and a displaying means for displaying the program guide information detected by this information detecting means. In this receiving apparatus, the displaying means does not display the program guide information in relation to the program information not existing in the NIT detected by the table detecting means.
In the present invention, said display means does not display the program guide information in relation to the program information not existing in said network information table detected by said table detecting means. That is, said display means does not display the program guide information in relation to the program information other than the one existing in said network information table detected by said table detecting means. Therefore, program guide information displayed by the displaying means is only the guide information of program that can be received. Therefore, viewers can receive all programs selected on the basis of the program guide information. Accordingly, it does not occur that viewers cannot receive the program selected based on the program guide information. This prevents confusion of viewers.
A further understanding of the nature and advantages of the invention may be realized by reference to the following portions of the specification and drawings.